• Title/Summary/Keyword: PP&S

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Migration Behavior of Fatty Materials into the Selected Plastic Film During Storage (저장 조건에서의 플라스틱 포장재와 지방산의 전이도 측정)

  • An, Duek-Jun
    • KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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    • v.8 no.2
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    • pp.39-43
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    • 2002
  • Increasing use of plastics in food packaging materials has led to the issue of food-plastic packaging materials's mutual interactions. Although the plastic packaging materials are generally considered as inert, migration and sorption of fatty materials are some of the problems associated with their use. So, this work investigated the compatibility of three structurally different polymers, polypropylene (PP), polyethyleneterephthalate (PET) and ethylene vinyl alcohol copolymer (EVOH) with some structurally different food fats. The main goal was to study the sorption of food fats by the plastic films and to see what extent mechanical properties of the plastic films was affected by plasticization effect due to sorption of fatty materials. PP, PET, and EVOH films was immersed in pure triglycerides, and then extracted with hexane and analyzed for the amounts of fat migrated. The sorbed films were also investigated for change in mechanical properties. Result showed that structural factor of the films and fatty materials plays important role in th migration process. The fat with the simplest structure are migrated more easily that the fat with more complex structure. However, structural effect of migration was varied according to degree of crystallinity and density of plastic films. In addition to that, polarity of plastic film was affected migration of fatty materials significantly. Additional research is needed to justify the reason why migration of fatty materials into the films was affected by polarity and structural integrity.

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Clinical Study of Ventricular Septal Defect (심실중격결손의 임상적 고찰)

  • Kim, Gyu-Tae;Lee, Jong-Tae;Lee, Jae-Seong
    • Journal of Chest Surgery
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    • v.18 no.2
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    • pp.157-164
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    • 1985
  • Our series comprised 68 patients of ventricular septal defect who underwent open heart surgery at the Department of Thoracic and Cardiovascular Surgery, School of Medicine, Kyungpook National University, from January, 1980 to September, 1984. Of the 68 patients, 47 patients were male [69.1%] and 21 patients were female [30.9%]. Their age ranged from 3 years to 27 years, and the mean age was 10.1 years. Upon Kirklin`s anatomical classification, type I constituted 29.4%, type II 69.1%, type III 1.5%, and type IV 1%. The cardiac anomalies associated with ventricular septal defect were 21 in all; 5 PS, 4 Aortic insufficiency, 2 ASD, 4 Patent foramen ovale, and 1 Patent ductus arteriosus. Upon the data of cardiac catheterization, most of the patients had Qp/Qs of 1.4-1.8, Pp/Ps of 0.25 or less and Rp/Rs of 0.25 or less. There was no significant correlationship between the rate of operative complication & mortality and the increase of Qp/Qs, Pp/Ps, and Rp/Rs. The values of Qp/Qs, Pp/Ps and Rp/Rs were correspondingly increased according to increment of the defect size. 20 patients developed postoperative complications, such as 4 acute respiratory failure, 3 reexploration due to massive bleeding, 1 low cardiac output, 1 patch detachment, and 2 air embolism. Operative mortality rate was 7.4% [5 cases] among 68 patients.

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Studies on the Separation of X and Y-Chromosome bearing Spermatozoa by Sedimentation in Boar Semen (침전에 의한 돼지의 X-와 Y-정자의 분이에 관한 연구)

  • 정용기;이용빈;임경순
    • Korean Journal of Animal Reproduction
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    • v.5 no.2
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    • pp.49-55
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    • 1981
  • This experiment was conducted to investigate the effects of temperature and time of sedimentation and dilutor on the a, pp.arance of B-body in top and bottom fractions at separation of X and Y- chromosome bearing spermatozoa in boar semen. 1. The top fraction showed higher a, pp.arence rate of B-body than the bottom. 2. Sixty minutes at 5 and 15$^{\circ}C$ and 90 min, at 25$^{\circ}C$ showed highest difference of B-body a, pp.arence rate between top and bottom fractions. The highest difference was shown in the treatments of Sg at 5$^{\circ}C$, C at 15$^{\circ}C$ and P at 25$^{\circ}C$. 3. The highest difference was shown in the treatments of 25$^{\circ}C$ and Sg for 30 min, 15$^{\circ}C$ and P for 60 min. and 25$^{\circ}C$ and P for 90 min. 4. Sixty minutes in C, P, S and Sg dilutors showed the highest difference. 5. 25$^{\circ}C$ of the temperature levels, 60 min of the time levels and P of the dilutor levels showed the highest difference. 6. The difference was given due to the individual boar.

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Development of polypropylene-clay nanocomposite with supercritical $CO_2$ assisted twin screw extrusion

  • Hwang, Tae-Yong;Lee, Sang-Myung;Ahn, Young-Joon;Lee, Jae-Wook
    • Korea-Australia Rheology Journal
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    • v.20 no.4
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    • pp.235-243
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    • 2008
  • The aim of this study is to explore the possibility of incorporating supercritical carbon dioxide ($scCO_2$) into twin screw extrusion process for the production of polypropylene-clay nanocomposite (PPCN). The $CO_2$ is used as a reversible plasticizer which is expected to rapidly transport polymeric chains into the galleries of clay layers in its supercritical condition inside the extruder barrel and to expand the gallery spacings in its sub-critical state upon emerging from die. The structure and properties of the resulting PPCNs are characterized using wide-angle X-ray diffraction (WAXD), transmission electron microscopy (TEM), rheometry, thermogravimetry and mechanical testing. In the processing of the PPCNs with $scCO_2$, optimum $scCO_2$ concentration and screw speed which maximized the degree of intercalation of clay layers were observed. The WAXD result reveals that the PP/PP-g-MA/clay system treated with $scCO_2$ has more exfoliated structure than that without $scCO_2$ treatment, which is supported by TEM result. $scCO_2$ processing enhanced the thermal stability of PPCN hybrids. From the measurement of linear viscoelastic property, a solid-like behavior at low frequency was observed for the PPCNs with high concentration of PP-g-MA. The use of $scCO_2$ generally increased Young's modulus and tensile strength of PPCN hybrids.

Modulatory Activity of Bifidobacterium sp. BGN4 Cell Fractions on Immune Cells

  • Kim Nam-Ju;Ji Geun-Eog
    • Journal of Microbiology and Biotechnology
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    • v.16 no.4
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    • pp.584-589
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    • 2006
  • Bifidobacteria has been suggested to exert health promoting effects on the host by maintaining microbial flora and modulating immune functions in the human intestine. We assessed modulatory effects of the different cell fractions of Bifidobacterium sp. BGN4 on macrophage cells and other immune cells from the spleen and Peyer's patches (PP) of mouse. Cell free extracts (CFE) of the BGN4 fractions induced well-developed morphological changes in the macrophages and increased the phagocytic activity more effectively than other fractions in the mouse peritoneal cells. Nitric oxide (NO) production was significantly reduced by both the cell walls (CW) and CFE in the cultured cells from the spleen and PP. The production of interleukin-6 (IL-6) and interleukin-10 (IL-10) was eminent in the spleen cells treated with experimental BGN4 cell fractions. However, in the PP cells, IL-6 was slightly decreased by the treatment with the whole cell (WC) and CW, whereas IL-10 was significantly increased by the treatment with the CW and CFE. These results suggest that different types of bifidobacterial cell fractions may have differential immunomodulatory activities depending on their location within the host immune system.